A Brazilian airline is asking its employees to be on the lookout for a former Guantanamo Bay detainee who was resettled in Uruguay.

The alert about Syrian native Abu Wa'el Dhiab adds to a growing mystery about his whereabouts. Uruguayan authorities have insisted for weeks that he is visiting neighboring Brazil and that as a refugee he is entitled to leave Uruguay.

However, the Brazilian government has said there is no record of Dhiab entering the country.

Avianca Airlines spokesman Danilo Alves told The Associated Press on Monday that the alert was issued internally to employees but declined to give any more details.

The alert, published by the Argentine web news portal Infobae, warns employees that Dhiab may be using a fake passport.